Research: FlightSQL context improvements

[sergiimk]

This is a research ticket to see how we can avoid the expensive table pre-registration procedure during the QueryManager::create_context procedure.

Ideas:

• Check how FlightSQL queries look like during table selection in Superset to understand whether we can provide partial results based on like pitern
• Investigate low-level show tables handler that acts as a quick search in Platform and only returns subset of results based on search pattern and returning only owned datasets when pattern is not specified
• Investigate auto-registering datasets in DataFusion as fallback on “table not found”
• Consider “user workspace” idea when user has to add / star a dataset for it to appear in their show tables results